1. Field of the Invention
The present invention relates to a black smoke exhaust purification apparatus for a diesel engine.
2. Related Art
A conventional exhaust after treatment device (a black smoke exhaust purification apparatus) is suggested for use in an automobile and is arranged in series thereon in order of an exhaust inlet (a heater), an oxidation catalyst and a particulate filter (see FIG. 13). A temperature of the particulate filter needs to be increased so as to regenerate the particulate filter and is mainly increased due to heat caused by exhaust gas. The oxidation catalyst also play a role in increasing the temperature of the particulate filter by obtaining oxidative heat from CO or HC soon after the particulate filter accompanying purifications of them. The particulate filter is made of a ceramic, and there is a possibility that a crack is caused due to the temperature difference in the particulate filter when exhaust gas is concentrated at one site. Various structures are suggested so as to equalize the temperatures in the particulate filter in response to the problem (for example, see Patent Literatures 1, 2, 3 and 4).
In general, the exhaust inlet is provided with a space at the opposite side of the particulate filter over the oxidation catalyst (a space at the upstream side of the oxidation catalyst) so that exhaust gas directly enters from the exhaust inlet. With regard to an exhaust outlet, a device which the particulate filter is provided on the outer periphery thereof with a space through which exhaust gas is discharged, is suggested so as to keep the outer side of the particulate filter warm (for example, see Patent Literature 5.) But in many of the devices, exhaust gas is discharged directly, or via a resonant chamber and the like, from a space on the side of the particulate filter.
In case of an industrial engine, since the exhaust after treatment device is installed in various forms and a space in a mounted portion is limited, there are various shapes of mufflers. Especially, exhaust gas enters from the side surface portion of the muffler in many of the engines. Also, with regard to the industrial engine, for example, an application in which a filter case having a sound deadening performance is installed at the present muffler placement instead of the muffler, is filed (for example, Patent Literatures 1 and 6).    Patent Literature 1: the Japanese Patent Laid Open Gazette 2005-16374    Patent Literature 2: the Japanese Patent Laid Open Gazette 2006-7100    Patent Literature 3: the Japanese Patent Laid Open Gazette 2006-16991    Patent Literature 4: the Japanese Patent Laid Open Gazette 2006-88027    Patent Literature 5: the Japanese Patent Laid Open Gazette 2003-49634    Patent Literature 6: the Japanese Patent Laid Open Gazette 2003-120277